The invention relates to a wood burning stove (also useful for burning certain types of coal) with a water circulating structure within the stove. The stove according to the present invention is constructed in such a manner that it can efficiently and effectively heat an average three bedroom home, while at the same time providing at least a large part of the heating requirements for a domestic hot water supply. A typical stove according to the present invention could have a peak burn power of about 150,000 BTUs an hour, and transfer that heat into a hydronic space heating system, and (if desired) a domestic hot water supply, such that the exterior walls of the stove remain generally comfortable to the touch.
As is conventional in water circulating stoves, the stove according to the invention includes a plurality of walls defining a fire chamber, with the flue disposed in one of the walls; a door in one of the walls providing access to the fire chamber; and means for circulating water through the fire chamber to heat the water when a fire is burning in the fire chamber. According to the invention, the circulating means include first and second manifolds, which are supported--as by a metal plate defining a wall of the stove opposite the wall containing the door--so that they extend generally horizontally, with the first manifold vertically above the second. A plurality of fuel supporting pipes physically and fluidly interconnect the manifolds. The pipes preferably each include a first, generally horizontally extending, portion connected to the first manifold, a second generally vertical portion connected to the first portion, and a third portion interconnecting the second portion and the second manifold, the third portion disposed at a positive angle with respect to the horizontal. Third portions of the fluid supporting pipes on opposite sides of the second manifold define a "V" configuration.
A liquid inlet is provided to the second manifold, and a liquid outlet is operatively connected to the first manifold. The inlet and outlet are adapted to be operatively connected to a hydronic space heating system for heating areas--such as rooms of a house--remote from the stove itself. The inlet includes an inlet pipe which extends concentrically within the tubular second manifold, a majority of the length thereof.
Defining part of the outlet from the first manifold is a container which has a cross-sectional area significantly greater than the cross-sectional area of the first manifold, with an outlet pipe connected to the container. The container is connected to the metal plate defining the manifold-supporting wall of the stove. The container also supports a heat exchanger, which preferably comprises a thinned copper tube having an inlet and an outlet. The thinned copper tube is supported so that it extends generally horizontally, and extends within, and over a substantial portion of the length of, the first manifold. The heat exchanger is adapted to be connected up to a hot water tank and a conventional domestic hot water supply system.
In order to provide for safe operation of the stove, pressure relief means are associated with the water circulating means to allow release of pressure from the water circulating means should it build up to a pressure greater than a predetermined "safe" value. Also, one or more electric resistance coils are supported by the container, and connected up to a source of EMF, for heating liquid within the container when the stove is to be left unattended for long periods of time in order to prevent freezing of liquid within the water circulating means. The electric resistance coils also provide electrically heated water to a hydronic system.
It is the primary object of the present invention to provide an efficient wood burning, water circulating stove, for providing space heating and/or domestic hot water heating for a dwelling. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.